A vehicle may include an adaptive front steering system (AFS) system that may add and subtract an angle between the driver steering wheel input and the steering gear input shaft. The adaptive front steering system may include an electronic control unit (ECU), a motor, a gear and a locking device. The locking device may provide a mechanical connection between the steering wheel and wheels during power-off of the AFS system (i.e., before and/or after shutting down the engine) and it may lock the actuator in case of a failure in the AFS system.
The locking unit of the AFS system may include a solenoid including a pin and a spring for biasing the pin in a direction toward an extended position in engagement with a locking disc connected to a shaft of the motor of the AFS system.
When the pin moves into and/or out of engagement with the locking disc, the pin may generate an objectionable noise, e.g., a clicking noise. For example, to engage the solenoid with the locking plate, a duty cycle to the solenoid is reduced and the pin begins to move toward the extended position under the bias of the spring. When the pin makes contact with the locking plate, an objectionable clicking noise may be produced. A similar clicking noise may be produced when the solenoid is disengaged from the locking disc when the pin impacts internal components of the solenoid. Despite this long known problem with such systems, there remains a very significant need for an effective solution to eliminate the noise of such systems and yet be operable in the operating environment of the AFS system.